On a night that saw debutant Kirisome Auva'a score his first try in Souths colours, Nathan Merritt etched his name in the club's history books when he crossed for the 145th four-pointer of a stellar career.

Merritt's 55th-minute effort was greeted with great delight by his teammates as he finally usurped Benny Wearing's club try-scoring record that had stood since 1933.

But it was the first-half defensive effort that set up the win for Michael Maguire's side.

An early penalty from Adam Reynolds broke the deadlock, but it was one of the few occasions Souths spent any time in Penrith territory as the home side dominated possession.

Some poor handling in sodden conditions did not help the visitors's cause, but they simply repelled everything the Panthers threw at them with some brilliant goal-line defence.

All Penrith had to show for its efforts was Jamie Soward's penalty and its inability to cross the line galvanised the Rabbitohs in the second half.

Former Melbourne junior Auva'a crossed just after the restart before Merritt went over in the left corner when he latched onto Dylan Walker's pass.

Penrith continued to probe, but was frustrated by Souths' defence who did not miss a tackle until the 65th minute of the game.

Young back-rower Kyle Turner iced the game with a try under the posts nine minutes from time to ensure a second straight win for Maguire's side.